Diagnostic ultrasound for nerve transection.

The current approach for localizing and assessing the severity of traumatic peripheral nerve injuries involves clinical evaluation and electrodiagnostic studies. However, the ability of this approach to determine the extent of nerve damage within the first 6 weeks after trauma is limited. This is problematic because outcome is improved with early surgical intervention after complete nerve transection. This led us to explore alternative techniques, such as imaging, for assessing peripheral nerve injuries. Twelve fresh cadavers were obtained and after inspection 20 arms were deemed suitable for inclusion in the study. Random sites were transected in median, ulnar, and radial nerves, and sham skin incisions were performed throughout the arm. These nerves were then systematically scanned by an ultrasonographer blinded to the nerve transection sites, who made a final decision as to whether the nerve was transected. High-resolution ultrasound was able to identify transected nerves in the upper extremity with 89% sensitivity and 95% specificity in fresh cadavers. This proof-of-concept study shows that ultrasound can accurately identify nerve transection, which should lead to further ultrasound studies in patients with traumatic peripheral nerve injuries.